If the coming winter months ice over Lake Superior at Apostle Islands National Lakeshore and turn the mainland caves into castles of ice, it'll cost you a little to see them.

Once the snow piles up in Iowa, you can head to Herbert Hoover National Historic Site for a snowshoe trek through the park's tallgrass prairie.

The clock is ticking down to the National Park Service's centennial in 2016, and the focus of the PR campaign has been on attracting a new generation to the parks. But how far should it go in trying to lure millennials and a more diverse visitor? At least one Park Service veteran wants to see the agency "regain the spiit of John Muir and Teddy Roosevelt."

With long, cold, snowy months descending on the northern half of the country, it's not a bad time to cast your eyes to the south and national parks where you can find warm weather, sandy beaches, and plenty of sunshine.